Cholecalciferol plus calcium suppresses abnormal PBMC reactivity in patients with multiple sclerosis

Abstract

Context: The active metabolite of vitamin D, 1,25-dihydroxyvitamin D [1,25(OH)(2)D], is a potent modulator of immune cells in vitro.

Objective: Our objective was to determine whether the sun-dependent nutrient, cholecalciferol, can alter disease-associated cellular immune abnormalities in patients with multiple sclerosis (MS).

Design: This was an open-label, 12-month, randomized controlled trial.

Setting: Patients with MS were recruited from the MS Clinic at St. Michael's Hospital, Toronto.

Patients: Forty-nine patients were matched (for age, sex, disease duration, disease-modifying drug, and disability) and enrolled (treated n = 25; control n = 24). Four patients were lost to follow-up (n = 2 from each group).

Intervention: Treated patients received increasing doses of cholecalciferol (4,000-40,000 IU/d) plus calcium (1200 mg/d), followed by equilibration to a moderate, physiological intake (10,000 IU/d). Control patients did not receive supplements.

Main outcome measures: At enrollment and at 12 months, peripheral blood mononuclear cell (PBMC) proliferative responses to disease-associated, MS-relevant, and control antigens were measured, along with selected serum biochemical markers.

Results: At 12 months, mean serum 25-hydroxyvitamin D [25(OH)D] concentrations were 83 ± 35 nmol/liter and 179 ± 76 nmol/liter in control and treated participants, respectively (paired t, P < 0.001). Serum 1,25(OH)(2)D did not differ between baseline and 1 yr. In treated patients, 12-month PBMC proliferative responses to neuron antigens myelin basic protein and exon-2 were suppressed (P = 0.002). In controls, there were no significant changes in disease-associated PBMC responsiveness. There were no significant differences between groups in levels of selected biomarkers.

Interpretation: MS-associated, abnormal T cell reactivities were suppressed in vivo by cholecalciferol at serum 25(OH)D concentrations higher than 100 nmol/liter.

Trial registration: ClinicalTrials.gov NCT00644904.

Fig. 1.

Study timeline. Supplementation schedule presented was for the treated patients only; control group participants received no intervention. Measurements were conducted as indicated at time points marked by (blood drop, indicating blood collection).

Fig. 2.

Proliferation responses to antigen challenge at baseline and end of study in control and treated groups. Thymidine incorporation was measured in response to antigen stimulation. Boxes represent the central 50% of values, whiskers the highest/lowest values, and the line represents the median value. a, Significant difference within group (baseline vs. end of study) (Wilcoxon, P < 0.01); b, difference between groups (control vs. treated) in change from baseline (Wilcoxon, P < 0.01).

Fig. 3.

Proliferation scores decrease with increasing serum 25(OH)D concentrations. Change in total proliferation scores is plotted against the change in serum 25(OH)D concentration between baseline and 1 yr. Regression analysis revealed a significant negative correlation (Spearman ρ = −0.419; P = 0.005).